The present invention relates to a technology for manufacturing a semiconductor device, and particularly to a technology effective if applied to a method of manufacturing a semiconductor device having a nonvolatile memory, which is mounted on a system LSI (Large Scale Integrated Circuit) or the like.
As a general-purpose microcomputer equipped with a nonvolatile memory which continues to retain memory information even if power is turned off, may generally be mentioned an OTP (One Time Programmable) ROM (Read Only Memory) built-in microcomputer or a flash memory built-in microcomputer intended for a customer-based soft development or debugging, or a mask ROM built-in microcomputer intended for a cost reduction at mass production, or the like. Here, an OTPROM is a nonvolatile memory (inclusive of an EPROM (Erasable Programmable Read Only Memory)) capable of writing memory contents therein only once by a customer, a flash memory is a nonvolatile memory (inclusive of EEPROM (Electrically Erasable Programmable Read Only Memory)) capable of electrically effecting all of erasure/reprogramming of memory information, and a mask ROM is a program-fixed nonvolatile memory which writes memory information therein in a manufacturing process.
Incidentally, a technology for allowing a plurality of types of semiconductor elements to be formed on a sheet of semiconductor wafer and enhancing production efficiency of various kinds of semiconductors has been described in, for example, Unexamined Patent Publication Hei 7(1995)-283287 of Iwasaki et al.
Further, a simple manufacturing method of a semiconductor device, which is capable of effecting writing on a read only memory element of the semiconductor device having a flash memory element and a read only element together during a semiconductor device manufacturing process and carrying out reading even without writing after its commercialization, has been disclosed in, for example, Unexamined Patent Publication Hei 5(1993)-304277 of Yamamoto et al.